1. Field of the Invention
The present invention is directed to the conversion of high-level graphics into pixel codes for display on a display device and, more particularly, to a raster graphics engine with speed and flexibility for use in radar applications.
2. Description of the Related Art
The term "graphics engine" is used to describe a data processing device which takes high-level graphics, such as text characters, symbols of various sizes, such as rectangles, circles and triangles, line segments and arcs, etc., and outputs signals which can be used in driving a display device such as a cathode ray tube (CRT) in a computer monitor. There are many types of devices which can be used as a graphics engine. The more powerful personal computers include simple graphics engines which are typically so slow that they cannot be used for real-time display of data. Slightly more powerful are work stations, such as those manufactured by SUN or APOLLO, which come closer to real-time operation, but typically exhibit annoyingly slow response in performing certain functions, such as zoom or pan. Due to the lack of speed and even slower speeds which were available in years past, applications demanding faster response, such as air traffic control radar or weapons control radar, typically use hardware specifically designed for each application. While it was possible to obtain reasonably quick responses using such unique hardware designs, when the functions to be performed by such applications are expanded, it is necessary to redesign significant portions of the hardware.
Furthermore, there are several different basic types of high-level graphics. Fixed size symbols, i.e., text, is easily converted into display data when no other type of graphics is to be displayed. However, high-level graphics may also define vectors or solid polygons of various sizes, shapes and shading. When one of these other types of high-level graphics are mixed with symbols, it often becomes much more difficult to generate the fixed size symbols. Also, some applications display more than one set of video data. For example, radar applications typically combine a display of target tracks with identifying textual information. The sweep of the radar and textual information are superimposed on a single screen. None of the existing systems provide both flexibility and high speed response.